The fire was reported about 3:15 p.m. near Vic Hubbard Speed and Marine auto supply at 411 W. A St., near an onramp to I-880, Capt. Thor Poulsen said.

A column of smoke could be seen from the highway rising into the still air, and motorists were slowing down to see what was causing the fire, complicating traffic in the area.

The driver of the car, an older model Mercedes, had filled the vehicle with low-octane gasoline and, noticing it was running rough, had stopped at the supply store to buy some octane booster. The driver added the booster to the tank and was letting the car idle for a bit when it caught fire.

Firefighters had difficulty putting out the fire and called a second engine about 3:22 p.m. to help add foam to control the blaze.